Web Authentication ProtocolOAuth Working Group T. Lodderstedt, Ed.
Internet-Draft Deutsche Telekom AG
Intended status: Standards Track S. Dronia
Expires: November 27, 2012April 9, 2013
M. Scurtescu
Google
May 26,October 6, 2012
Token Revocation
draft-ietf-oauth-revocation-00draft-ietf-oauth-revocation-01
Abstract
This draft proposes an additional endpoint for OAuth authorization
servers for revoking tokens.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on November 27, 2012.April 9, 2013.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Token Revocation . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. JSONPCross-Origin Support . . . . . . . . . . . . . . . . . . . . . . . 5
3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 56
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 56
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.1. Normative References . . . . . . . . . . . . . . . . . . . 6
6.2. Informative References . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
The OAuth 2.0 core specification [I-D.ietf-oauth-v2] defines several
ways for a client to obtain refresh and access tokens. This
specification supplements the core specification with a mechanism to
revoke both types of tokens. A token is the external representation
of an access grant issued by a resource owner to a particular client.
A revocation request may discard the actual token as well as other
tokens based on the same access grant and the access grant itself.
This mechanism facilitates the following use cases:
o The end-user triggers revocation from within the client that sends
the appropriate revocation request to the autorization server.
From the end-user's perspective, this looks like a "logout" or
"reset" function.
The request causes the removal of the client
permissions associated withclient's access grant the
particular token to accessrefers to. From the end-user's protected resources.perspective, this
looks like a "logout" or "reset" function. This use case makes it
even more comfortable to the end-user to revoke his access grant
immediately via the client.
o In contrast to revocation by a client, the authorization server
(or a related entity) may offer its end-users a self-care portal
to delete access grants given to clients independent of any token
storing devices. Such a portal offers the possibility to an end-
user to look at and revoke all access grants he once authorized.
In cases the token storing device is not available, e.g. it is
lost or stolen, revocation by a self-care portal is the only
possibility to limit or avoid abuse.
In the end, security, usability, and ease of use are increased by
token revocation.
By using an additional endpoint, the token revocation endpoint,
clients can request the revocation of a particular token. Compliant
implementation MUST support the revocation of refresh tokens, access
token revocation MAY be supported.
2. Token Revocation
The client requests the revocation of a particular token by making an
HTTP POST request to the token revocation endpoint. The location of
the token revocation endpoint can be found in the authorization
serversserver's documentation. The token endpoint URI MAY include a query
component.
Since requests to the token revocation endpoint result in the
transmission of plain text credentials in the HTTP request, the
authorization server MUST require the use of a transport-layer
security mechanism when sending requests to the token revocation
endpoints. The authorization server MUST support TLS 1.0
([RFC2246]), SHOULD support TLS 1.2 ([RFC5246]) and its future
replacements, and MAY support additional transport-layer mechanisms
meeting its security requirements.
The client constructs the request by including the following
parameters using the "application/x-www-form-urlencoded" format in
the HTTP request entity-body:
token REQUIRED. The token that the client wants to get revoked.
Note: the authorization server is supposed to detect the
token type automatically.
The client also includes its authentication credentials as described
in Section 2.3. of [I-D.ietf-oauth-v2].
For example, a client may request the revocation of a refresh token
with the following request (line breaks are for display purposes
only):
POST /revoke HTTP/1.1
Host: server.example.com
Content-Type: application/x-www-form-urlencoded
Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
token=45ghiukldjahdnhzdauz&
The authorization server first validates the client credentials (if
present)(in
case of a confidential client) and verifies whether the client is
authorized to revoke the particular token based on the client
identity and its policy. For example, only the client the token has
been issued for might be allowed to revoke it. It is also
conceivable to allow a dedicated user self-care portal to revoke all
kinds of tokens.
In the next step, the authorization server invalidates the token.token and
the respective access grant. If the particular token is a refresh
token and the authorization server supports the revocation of access
tokens, then the authorization server SHOULD also invalidate all
access tokens based on the same access grant.
Whether the revocation takes effect instantly or with some delay
depends on the architecture of the particular deployment. The client
MUST NOT make any assumptions about the timing and MUST NOT use the
token again.
If the processed token is a refresh token and the authorization
server supports the revocation of access tokens, then the
authorization server SHOULD also invalidate all access tokens issued
for that refresh token.
The authorization server indicates a successful processing of the
request by a HTTP status code 200. Status code 401 indicates a
failed client authentication, whereas a status code 403 is used if
the client is not authorized to revoke the particular token. For all
other error conditions, a status code 400 is used along with an error
response as defined in section 5.2. of [I-D.ietf-oauth-v2]. The
following error codes are defined for the token revocation endpoint:
unsupported_token_type The authorization server does not support the
revocation of the presented token type. I.e. the client
tried to revoke an access token on a server not supporting
this feature.
invalid_token The presented token is invalid.
2.1. JSONPCross-Origin Support
The revocation endpoint MAYrevokation end-point SHOULD support CORS [W3C.WD-cors-20120403]
if it is aimed at use in combination with user-agent-based
applications. In addition, for interoperability with legacy user-
agents, it MAY offer JSONP [jsonp] by allowing GET requests with an
additional parameter:
callback The qualified name of a JavaScript function.
Example request:
https://example.com/revoke?token=45ghiukldjahdnhzdauz&
callback=package.myCallback
Successful response:
package.myCallback();
Error response:
package.myCallback({"error":"invalid_token"});
Clients should be aware that when relying on JSONP, a malicious
revokation end-point may attempt to inject malicious code into the
client.
3. Acknowledgements
We would like to thank Michiel de Jong, Doug Foiles, Paul Madsen,
George Fletcher, Sebastian Ebling, Christian Stuebner, Brian
Campbell, Igor Faynberg, Lukas Rosenstock, and Justin P. Richer for
their valuable feedback.
4. IANA Considerations
This draft includes no request to IANA.
5. Security Considerations
All relevant security considerations have been given in the
functional specification.
6. References
6.1. Normative References
[I-D.ietf-oauth-v2]
Hammer-Lahav, E., Recordon, D., and D.
Hardt, D., "The OAuth 2.0 Authorization Framework", draft-ietf-oauth-v2-26draft-ietf-oauth-v2-31 (work in progress), MayAugust 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
RFC 2246, January 1999.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
6.2. Informative References
[W3C.WD-cors-20120403]
Kesteren, A., "Cross-Origin Resource Sharing", World Wide
Web Consortium LastCall WD-cors-20120403, April 2012,
<http://www.w3.org/TR/2012/WD-cors-20120403>.
[jsonp] Ippolito, B., "Remote JSON - JSONP", December 2005.
Authors' Addresses
Torsten Lodderstedt (editor)
Deutsche Telekom AG
Email: torsten@lodderstedt.net
Stefanie Dronia
Email: sdronia@gmx.de
Marius Scurtescu
Google
Email: mscurtescu@google.com